Portable spirometer



FIG. 1 is a front, top and left side perspective view of the portable spirometer according to the present invention;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is an exploded rear perspective view of the portable spirometer shown in FIG. 1 when separated into three parts;

FIG. 8 is a front, top and left side perspective view of the connecting middle piece of the portable spirometer shown separately for clarity of the illustration; and,

FIG. 9 is a front, bottom and left side perspective view of the connecting middle piece of the portable spirometer. 

CLAIM The ornamental design for a portable spirometer, as shown and described. 